Text below is based on Asus F3H but all recent laptops use almost the same components.

DISCLAIMER
Please notice that you are using this instruction at your own risk – you can break your computer or hurt yourself. So please read the whole article before you try to do actual upgrade. If you feel awkward using screwdriver, please ask your daddy to do it Following this instructions may void you warranty!

After this optimistic introduction, let’s move to the main topic. I am would like to apologize all the hardcore computer freaks for all those details – a lot of people still believe that computer is some kind of magical device

What will we need:

small Phillips screwdriver

appropriate memory card

a little patience

I used something like this to disassemble my laptop:

As for memory card, Asus documentation tells us this:
Main Memory: 2 x SODIMM socket for expansion up to 2048MB
DDR2-533/667 DRAM support

It is worth to check it yourself because you can easily buy the wrong memory card. Ideally, try to disassemble your computer, remove card which is currently installed and then try to find something with the same parameters. I would like to draw your attention to the fact that Asus says two slots to EXTEND ABOUT MAX 2GB(sic!). I think it means that we can use no more than 1GB memory card for each of the slots (but I may be wrong)!

Ok, let’s disassemble the laptop. First you should remove the battery – we don’t want the computer to turn on while we are digging in it’s guts. After removing the battery we need to unscrew 7 screws from upper right part of the housing, no need to unscrew one in the top left corner:
After unscrewing the screws very gently take off the lid. If it cannot be easily removed, investigate the problem instead of using brute force!
After removing the lid you should see something like this:
We are interested in Memory Slot 1 (where our current card sits) and Memory Slot 2 – where we will install our new purchase.

If you want to remove the card you will first have to GENTLY release the clips(marked on picture as ZATRZASKI) holding it in, then GENTLY raise it and pull it out.

Removed card looks like this:

Model number is PC2-5300S-555. HYS64T12(…) is the name of the manufacturer. According to this reference it is DDR2-667 memory, so you should buy SODIMM DDR2-667 PC2-5300 (unless you have different numbers, which is VERY possible). You should also check if it is similar visually – notch (key) should be in the same place.The card can be inserted into the slot only one way, if you try to put it wrong way it may break something (the card slot is much more fragile than standard DDR)!

Now when we saw our card, we can try to put it back and add the new one – that’s the whole upgrade
When inserting card into the slot, it’s very important that pins touch the slot – and sometimes it’s not so easy to achieve:
Once you inserted the card(s) GENTLY put the lid on and screw the screws – just two or three, so if anything doesn’t work, you don’t have to unscrew them all again. Put the battery back in. Start up the laptop, log in and check system info – if you have more memory than before, then CONGRATULATIONS – YOU’VE JUST UPGRADED YOUR LAPTOP’S MEMORY!
If something is wrong (ie computer doesnt turn on) DON’T PANIC! Check if you correctly put cards in, try to remove them and put them back in again. If you still have problems, remove the new card leaving just the old one – sometimes they don’t like each other. If nothing works, then we can start panicking

I didn’t have any bad experience, after assembling everything back, computer looks like this:

Ok, so now I am gonna order and install that memory

Update:
I’ve bought the memory: Kingston 1GB PC2-5300-CL5-200 Pin SODIMM (Assembled in China of course). It looks like this:
After receiving the package, I was very surprised that box was so long – I even thought that I’ve been sent wrong card. After opening the box it turned out that the card is indeed PC2-5300, but it looked very small. After disassembling the computer it turned out everything is ok – laptop cards are indeed very small.
After installing secondary card computer looks like this:
I’ve assembled everything back, crossed my fingers and turn the computer on. Everything worked fine, VISTA began to work like normal OS – about 3 times faster.System info reported 2GB of memory (please notice how Windows report my computer – lol)